A satellite communications system comprising a Hub station and a plurality of terminals, the system is configured to utilize a FWD link and a RTN link in accordance with adaptation techniques for relevant transmission properties (e.g. modulation, coding, transmission power, etc.) and to use adaptive margins to ensure proper reception of transmitted information under various link conditions. Methods are presented for determining said adaptive margins in real time or substantially in real time, and for setting relevant transmission properties in accordance with the determined margins. Adaptive margins may be determined either directly or following the determining of a link state for each of the FWD link and the RTN link.